The Swiss Tropical Institute, in close collaboration with national and international partners, has set up an interdisciplinary research and action programme to identify, test, and evaluate health interventions in nomadic pastoralist settings of Chad, Mali, and Mauritania. A combination of natural and social sciences and a transdisciplinary approach (combining scientific knowledge with the know-how of lay people) helped improve our understanding of the health priorities of the nomadic pastoralist (Schelling et al., 2007b). These assessments showed not one fully immunised nomadic child or woman while their cattle were largely vaccinated. Because preventive veterinary measures were designed at the outset to reach mobile populations, but public-health services were restricted to static health centres, failing to account for mobile lifestyles.
It became evident that mobile pastoralists are marginalised from development processes and vulnerable to exclusion from health services because of their geographical, social, and cultural environment. The weak infrastructure and quality of service in both the public health and veterinary sectors are closely related to resource constraints, especially lack of qualified staff. Therefore, professionals from theWorld Health Organisation and UN Food and Agriculture Organisation have suggested that public health and veterinary services should share resources.
Schwabe showed the outcomes and potential benefits of the “one medicine” as added value to public health that could not be achieved by the disciplinary approaches alone. He discussed the added values to public health of “one medicine” for food and nutritional security, zoonoses, comparative medical research, epidemiology and population medicine, environmental quality, mental health, and ethics. Zoonoses have been mostly eliminated in industrial countries with very large financial and organisational efforts focused on the animal reservoir. These solutions are not affordable in contemporary developing countries. The research of joint human and animal interventions and models, provide the approaches to assess the importance and epidemiological links of several zoonoses. The importance of brucellosis and Q-fever and their related animal hosts were identified in this way in Chadian nomadic pastoralists. New strategies can be found for developing countries to respond adequately to existing and emerging zoonoses (Schelling et al., 2005; Schelling et al., 2007a; Zinsstag et al., 2005).
Joint human and animal vaccination campaigns in Chad
According to the one medicine principles the STI is providing child vaccination, one of the most cost effective health interventions, in developing countries, in Chad (Schelling et al., 2005). Between 2000 and 2007, 15 vaccination campaigns for nomadic children and women were conducted among three ethnic groups (Fulani, Arabs, and Dazagada) in the areas where the communities concentrate during the dry season. With one exception, each vaccination campaign from 2000 to 2005 was composed of three vaccination rounds to enable full vaccination of children. The capacity of existing mobile veterinary infrastructures was extended to allow for simultaneous vaccination of people and animals in 11 out of the 44 vaccination rounds. The campaigns were set up with the local health and veterinary staff to avoid parallel structures and to make use of all existing infrastructure (cold chain and transportation).
In intervention zones, from 2000 to 2004 for the first time ~10% of nomadic children (>1–11 months of age) were fully immunized annually. Veterinarians vaccinated 149,255 livestock against anthrax, pasteurellosis, blackleg, and contagious bovine pleuropneumonia. After 3 visits from the vaccination team, 4,653 children <5 years of age were fully immunized against diphtheria, whooping cough (pertussis), and tetanus (DPT) and against polio; 7,703 women received at least 2 doses of tetanus vaccine (TT2+). More children and women were vaccinated per day during joint vaccination rounds than during vaccination of persons only and not their livestock (130 vs. 100, p<0.001) (Schelling et al., 2007a).
Evaluation of joint vaccination campaigns
These joint campaigns not only showed the technical and organisational feasibility of simultaneous vaccination, but in a first assessment also reduced costs by 15% compared with separate campaigns by sharing equipment and transport logistics between veterinary and public-health personnel (Béchir et al., 2004). To evaluate this intervention further on coverage and health impacts, estimates about population sizes and mortality in these highly mobile pastoralists settings are neccessary, even if there are estimates gained due to a Triple-catch mark-recapture based baysian model (Schelling et al., 2007a).
There is thus a need for demographic and health information surveillance for highly mobile people. Household methods are not applicable on mobile populations. New designs and tools trying to tackle the survey problem of mobile households are needed. A ”multiple mark-recapture” model combined with digital fingerprint technology is currently been tested. Expected results are estimates of the population size that is living in the dry season at the southern border of Lake Chad and estimates about child mortality in these nomadic populations. The same problem of laking baseline demographic date is facing us also on the livestock side to evaluate the livestock vaccinations. Therefor we conduct a “mark-recapture” experiment, where young cattle of the same nomadic communities have been earmarked to gain total livestock number estimates.
There is a considerable effect of joint interventions next to the reduction of costs: The veterinary and public health staff observed that when the two sectors were present together, pastoralist families vaccinated their livestock and children more spontaneously (Schelling et al., 2007a). An epidemiological survey in 1999 and 2000 showed that half of nomadic pastoralists had never visited a health centre and a first contact with the health staff was established during the vaccination programme. We can conclude that the institutional collaboration between public health and veterinary services seeks to strengthen health services for hard to reach populations by making better use of existing resources and to identify appropriate control strategies for zoonotic diseases. (Schelling et al., 2005)
Daniel Weibel
Esther Schelling, DVM PhD
Jakob Zinsstag, DVM PhD
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References
BÉCHIR,M., SCHELLING,E., WYSS,K., DAUGLA,D.M., DAOUD,S., TANNER,M. & ZINSSTAG,J. (2004) Approche novatrice des vaccinations en santé publique et en médecine vétérinaire chez les pasteurs nomades au tchad: expériences et coûts. Med Trop. 64, 497-502.
SCHELLING,E., BÉCHIR,M., ABDOULAYE,M.A., WYSS,K., RANDOLPH,T.F. & ZINSSTAG,J. (2007a) Human and Animal Vaccination Delivery to Remote Nomadic Families, Chad. Emerging Infectious Deseases 13, 373-379.
SCHELLING,E., WYSS,K., BÉCHIR,M., DAUGLA,D.M. & ZINSSTAG,J. (2005) Synergy between public health and veterinary services to deliver human and animal health interventions in rural low income settings. BMJ 331, 1264-1267.
SCHELLING,E., WYSS,K., DIGUIMBAYE,C., BÉCHIR,M., OULD TALEB,M., BONFOH,B., TANNER,M. & ZINSSTAG,J. (2007b) Towards adapted health services for nomadic pastoralists and their animals. In: Handbook of Transdisciplinary Research. A Proposition by the Swiss Academies of Arts and Sciences. (Ed. G.Hirsch Hadorn, H.Hoffmann-Riem, S.Biber-Klemm, W.Grossenbacher, D.Joye, Ch.Pohl, U.Wiesmann, E.Zemp & (Ed.)). Springer, Heidelberg.
ZINSSTAG,J., SCHELLING,E., WYSS,K. & MAHAMAT,M.B. (2005) Potential of cooperation between human and animal health to strengthen health systems. Lancet 366, 2142-2145.
Pictures (click to enlarge)
Left picture: Earmarking of a cattle for mark-recapture experiment to estimate total livestock numbers of nomadic people at the Lake Chad in dry season.
Right picture: Young Fulbe herder proudly showing ear decoration of his young cow.
